A magnetic random access memory (MRAM) element having a magnetic tunnel junction (MTJ) structure has attracted attention as one type of a memory element using a magnetoresistance effect element.
The MRAM element includes a multi-layer film configured of a hard-to-etch material such as a transition metal or a magnetic body. In manufacturing of such an MRAM element, for example, a platinum manganese (PtMn) layer is etched by using a mask containing tantalum (Ta). It is desirable that a shape to be formed by the etching has high verticality. In Patent Literature 1 described below, it is described that the platinum manganese layer is subjected to dry etching by generating plasma of etching gas containing hydrogen gas, carbon dioxide gas, methane gas and rare gas by using a tantalum layer as a mask. IN a method described in Patent Literature 1, the etching is performed while removing a deposition substance formed on the surface of the platinum manganese layer by the plasma of hydrogen contained in the etching gas, and thus, it is possible to process the platinum manganese layer with high verticality.